On the volumetric deformation of reconstituted soils

Abstract

This paper reviews the phenomenon of volumetric hardening, which is a common feature of the mechanical behaviour of many geo-materials. Three di!erent material idealizations have been proposed to describe this hardening, and the paper contains the corresponding mathematical formulation. These idealizations vary in their complexity and hence their ability to capture di!erent aspects of real material behaviour. Any of the three postulates can be implemented into most constitutive models. As a demonstration of their capabilities, the postulates have been implemented into the well-known modi"ed Cam Clay model, and computations are made with the resulting new constitutive models. It is seen that the new models can successfully represent important features of soil behaviour such as plastic yielding associated with loading inside the current virgin yield surface, the loosening or densifying of granular soils caused by shearing, and the accumulation of both volumetric and distortional deformation caused by repeated drained loading over a large number of cycles.

Fractional order model for granular soils under drained cyclic loading

“…However, to avoid excessive complexity in constitutive equations and especially the application in numerical simulation, N is included in the model formulation. Similar approaches were also used by Liu and Carter and Ni et al for modelling reconstituted soils. Substituting Equation into Equation , one has the following explicit formulation for the plastic modulus, H b : …”

“…theoretical, empirical and semi‐empirical approaches) in modelling the cyclic behaviour of granular soils. The first is the theoretical method, including the traditional elastoplasticity , generalized plasticity and bounding surface plasticity models , where the deformation of each loading cycle is strictly counted. This method reveals the deformation mechanism of soils subjected to cyclic loading.…”

Insight into Failure Mechanism of Large-Diameter Monopile for Offshore Wind Turbines Subjected to Wave-Induced Loading

“…According to Equation (1), the coefficient of friction = 0.37 is adopted. Figure 3 are the failure modes of instability of foundation-soil coupling system with wave height H = 1 m and H = 3 m. It is noted that under condition of wave height H = 3 m, the large-diameter monopile overturns shoreward, however under condition of H = 1 m, the foundation overturns seaward， according to investigation of the model tests, Liu and Carter (2000) concluded that under wave loading, the large-diameter cylindrical structure in soft ground may overturns seaward in a certain condition. In previous studies about the ultimate capacity of monopile in soft soil, the foundation overturns shoreward in any case in total stress finite element analyses (Fan, Luan, and Yang, 2006).…”

“…In order to consider the effect of stress path under cyclic loading, a loading surface is assumed in the inner region of the initial yield surface. The model includes the following parameters: M, the slope of critical state line in p-q space; and the slope of the virgin compression line and isotropic recompression line in e-lnp space respectively; v, Poisson's ratio; a model parameter considering OCR degradation of soil under cyclic loading (Carter, Booker, and Wroth, 1980;Liu and Carter, 2000). To minimize the error and improve the convergence, the implicit integration algorithm is adopted in this paper.…”

A general method for defining the number of cycles of repeated loading

“…This type of approach is clearly expedient and pragmatic, but for engineering application it is generally preferable to the alternative more rigorous approach [2,4,5]. The alternative method, which follows the strict requirements of the theory of elastoplasticity, is too complicated and also often yields less accurate numerical solutions.…”